Laterally double-diffused metal-oxide semiconductors (LDMOS) transistors are mainly used in power integrated circuit (IC). LDMOS transistors generally have advantages such as good thermal and frequency stabilities, higher gain and durability, lower feedback capacitance and thermal resistance, constant input impedance, and simpler biasing circuits. Thus, LDMOS transistors have been widely used in portable devices, radars, navigation systems, etc.
Taking an N-type device as an example, a conventional N-type LDMOS transistor is shown in FIG. 1. The LDMOS transistor includes a semiconductor substrate 100, a P-type well region 110 and an N-type drift region 120. The LDMOS transistor also includes a first shallow trench insulating (STI) structure 111 in the P-type well 110, a second STI structure 121 in the N-type drift region 120, and a gate structure 130 on the semiconductor substrate 100. The LDMOS transistor also includes a source electrode 112 and a body-tie electrode 113 on one side of the gate electrode 130. The source electrode 112 and the body-tie electrode 113 are located in the P-type well region 110 and may be separated from each other by the first STI structure 111. The LDMOS transistor further includes a drain electrode 122 located on the other side of the gate structure 130 in the N-type drift region 120.
However, a conventional LDMOS transistor often has a low breakdown voltage. The disclosed semiconductor device and the fabrication method for forming the semiconductor device are directed to solve one or more problems set forth above and other problems.